The present invention relates to devices for preventing collapse of the upper airway, methods for use thereof and systems and articles of manufacture including same. More particularly, the present invention relates to the use thereof for treatment of breathing disorders including, but not limited to, obstructive sleep apnea (OSA), apnea of infancy (AOI), sudden infant death syndrome (SIDS) and snoring. The present invention is further of devices, systems and methods which monitor parameters of air exhaled by a patient through such a device and of a physiologic status of a patient breathing through such a device. Devices of the present invention may, in some cases, take the form of a pacifier.
OSA is a syndrome with significant morbidity and mortality (C. Guilleminault and M. Partinen (eds.) (1990) “Obstructive Sleep Apnea Syndrome: Clinical; Research and Treatment”. Raven Press, New York, N.Y., USA, pp xv-xvii). OSA is caused by repeated collapse of soft tissues forming the walls of the upper airway in the sub-glottal region during sleep (C. Guilleminault and M. Partinen, Ibid.). Opening of this portion of the airway depends upon the balance between negative pressure, which is at least −7 or −10 cm H2O in normal quiet breathing (Levitzki MG (eds)(1986) “Pulmonary Physiology” McGraw—Hill Book Company, New York, N.Y., USA pp 37-40) outside the cavity caused by muscular action during breathing (e.g. action of the diaphragm and muscles surrounding the rib cage) and muscle tone in the upper airway itself (C. E. Sullivan et al., in C. Guilleminault and M. Partinen, Ibid., pp 49-69; S. T. Kuna et al. (1991) JAMA 266:1384-1389; J. E. Remmers et al., (1978) J. Appl. Physiol. 44:931-938; and D. J. Tangel et al. (1991) J. Appl. Physiol. 70:2574-2581). This repeated collapse of the upper airway causes a decrease in blood oxygen saturation which leads to sleep disturbances, fatigue and a general feeling of malaise in affected patients.
OSA is a common disorder with an estimated 2% of women and 4% of men being affected to a degree that treatment is advisable. This means that an estimated 12 to 18 million patients are affected in the USA. Since only about 7% to 18% of the population has been tested for this disorder, these estimates should be viewed as minimum estimates (C. Guilleminault in C. Guilleminault and E. Largesi (eds.) (1983) Raven Press, New York, N.Y., USA, pp 107-125; M. Partinen et al. (1988) Chest 94: 1200-1204; J. JE et al. (1988) Chest 94:9-14; National Commission on Sleep Disorders Research (1995) “Wake Up America: A National Sleep Alert” US Government Printing Office, Washington, D.C., USA, pp 2-10; T. Young et al. (1997) Sleep 20:705-706).
Currently accepted treatment for OSA typically includes continuous positive airway pressure (CPAP). CPAP, as currently practiced, involves connection of a pressurized air delivering device to the mouth or nose of the patient. This device typically is connected to a pressurized air source in the form of a compressor or tank with a regulator. These pressurized air supplies are expensive, large, and noisy.
Delivery of a constant flow of a breathable gas mixture through the device maintains a constant positive pressure in the upper airway. This constantly applied pressure prevents the collapse of the airway described hereinabove (C. E. Sullivan et al. (1981) Lancet 1:862-865; M. H. Sanders et al. (1983) Chest 83:144-145). CPAP is effective in treating OSA by preventing collapse of the airway and associated tiredness, fatigue, diminished intellectual function, and snoring and can even lengthen patient life expectancy (J. Hender et al. (1995) Eur. Respir. J. 8:222-229; H. Minemura et al. (1998) Intern. Med. 37: 1009-1013; C. Jenkinson et al. (1999) Lancet 353: 2100-2105).
In order to keep the pressure in the airway constant during inhalation and exhalation, a pressure valve is sometimes incorporated into the pressurized air delivering device. One such valve is taught by U.S. Pat. No. 4,298,023 for a spring loaded exhalation valve. Teachings of this patent specifically relate to treatment regimens which include a flow of gas delivered to the airway from a pressurized air supply.
However, patient compliance with CPAP treatment regimens is typically poor despite the proven efficacy of the treatment. Research suggests that 60 to 70% compliance is the norm and that the average patient use of CPAP is limited to 5 hours per night (N. P. Kribbs et al. (1993) Am. Rev. Respir. Dis. 147:887-895; H. Rauscher et al. (1993) Chest 103:1675-1680). In addition, many patients never begin treatment at all owing to the high cost of CPAP equipment.
Currently accepted treatment for AOI typically includes continuous positive airway pressure (CPAP). CPAP, as currently practiced, involves connection of a pressurized air-delivering device to the mouth or nose of the patient. This device typically is connected to a pressurized air source in the form of a compressor or tank with a regulator. These pressurized air supplies are expensive, large, and noisy.
Delivery of a constant flow of a breathable gas mixture through the device maintains a constant positive pressure in the upper airway. This constantly applied pressure prevents the collapse of the airway described hereinabove (C. E. Sullivan et al. (1981) Lancet 1:862-865; M. H. Sanders et al. (1983) Chest 83:144-145). CPAP is effective because it prevents collapse of the airway and associated tiredness, fatigue, diminished intellectual function, and snoring and can even lengthen patient life expectancy (J. Hender et al. (1995) Eur. Respir. J. 8:222-229; C. Jenkinson et al. (1999) Lancet 353: 2100-2105).
However, patient compliance with CPAP treatment regimens is typically poor despite the proven efficacy of the treatment. Research suggests that 60 to 70% compliance is the norm and that the average patient use of CPAP is limited to 5 hours per night (N. P. Kribbs et al. (1993) Am. Rev. Respir. Dis. 147:887-895; H. Rauscher et al. (1993) Chest 103:1675-1680). In addition, many patients never begin treatment at all owing to the high cost of CPAP equipment. Further, infants and children are less likely to comply than adults because they are incapable of understanding the need for treatment. Parents of these young patients are often disturbed by the “medical” appearance of conventional CPAP equipment and find it embarrassing to show to relatives and caregivers.
Further, sleep apnea in infants and young children is often treated by surgical intervention. Such intervention necessarily includes all of the risks associated with anesthesia and surgery.
Infants are typically obligatory nasal breathers (Shannon DC In: Disorders of the Respiratory Tract In Children—SIDS and Apnea in infancy Kendig & Chemick Eds (1990) W. B. Saunders Company, Philadelphia, Pa., USA pp 939-952.). Any change in airflows in the upper airways increase vulnerability to inadequate ventilation because: (1). the hypopharynx is shallow; (2) the tongue and epiglottis are more cephaled and (3) the mandible is more mobile (Tonkin S. (1975) Pediatrics 55:650-654). Normal infants typically have difficulty responding to nasal occlusion. Studies show that 44% of 6 week old infants struggled but failed to establish an oral airway when the nostrils were pinched for 25 seconds (Swift PGF et al (1973) Arch Dis Child 48:947-950). The physiologic basis for the failure to maintain adequate oral ventilation during occlusion in both normal and at risk infants is unknown. This mechanism has been suggested as a cause of AOI which can lead to SIDS (Anderson RB et al (1971) Biol Neonate 18:395-398.
U.S. Pat. No. 4,513,741 to Demi discloses an apparatus including a breathing tube and inflatable mouthpiece designed and constructed for use in animals, especially animals with an elongated snout. Demi neither hints nor suggests that the disclosed apparatus is useful or efficacious in treatment of sleep disorder such as AOI, SDS, or snoring. Further, the apparatus disclosed by Demi is wholly incompatible with human facial anatomy.
Thus, infants and young children suffering from excess nasal secretion tend to reject a pacifier during sleep in an effort to establish an alternate airway. This rejection may lead to sleep interruption when the comfort of sucking is subsequently missed.
There is thus a widely recognized need for, and it would be highly advantageous to have, devices for preventing collapse of the upper airway, methods for use thereof and systems and articles of manufacture including same. which are devoid of the above limitations. Further, monitoring of a parameter of exhaled air or patient physiology by such a device, system or method would increase utility thereof.